Railway signaling apparatus



Oct. 9, 1928.

A. A. SKENE RAILWAY 1S IGNALING APPARATUS Fil ed Aug. 4. 1926 2 Sheets-Sheet 11 INVENTOP I Q- a- 9M,

ecu-mm 1,687,111 A. A. SKENE- RAILWAY SIGNALING APPARATUS 2 Sheets-Sheet 2 Filed Aug. 4, 1926 INVENTOR I Patented Oct. 9, 1928.

f UNITED-Q. STATES;

Annnnw A. SKENE, or WIVLIKVINYSBURG, rnnNsYLv mA, ssIG R rO mm: UNION SWITCH '& SIGNAL COMPANY, or swissv Ln, IEQNNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY SIGNALING APPAR TUS.

' Application filed August 4, 1926. Serial No. 126,985.

-My invention relates to railway signaling apparatus and particularly to apparatus of the'type involving track circuits.

I will describe several forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of apparatus embodying my invention. Fig.1 is a sectional view across; the track rails shownin Fig. 1 and illustrating one location of, and one means for mounting, the auxiliary conductor B, Fig. 2 is a diagrammatic view showing a modification of the apparatus shown in Fig. l for varying the voltage supplied to the second winding of a two-winding relay, such modification also embodying my invention; Fig. 3 is a view showing a modification of the apparatus shown in Fig. 2, but involving a Wheatstone bridge arrangement and also embodying my invention. Fig. 4c is a modification of the apparatus shown in Fig. 3 and embodying my invention. Fig;

5 is a diagrammatic view showing a still further modification of my invention and including slow-acting means for varying the voltage applied to a relay winding. Similar reference characters refer to similar parts in each of the several views.

P f riiig l'rst to Fig. 1, the reference characters l and 1 designate the rails of a railway track, which rails are divided by in'sulated joints to form a section E-F. This section is provided with a track circuit comprising a transformer T having its secondary connected across the rails adjacent the point 'E, and a track relay R connected across thev rails adjacent the point F. The primary of transforn'ier T is connected WIth two terminals 8 and 9 which are in turn constantly connected with a source of alternating track circuit voltage which is not shown in the drawing. I I

Connected across the ra ls l and 1 of the ero -n E-F is areactanc-e A, and an auxil-fi iai lCldCtOl B is in contact with the track ballast for this section. As here shown, this conductor B extends the entire length of'the section, and as illustrated in Fig. 1*, it is preferably mounted on' the ties 10 midway between the two rails 1 and 1, so that it is in constant contact with the ties 10 and the ballast 11'. This particular means for mount-- i the con u o s not essen ial ,t my i1.

vention, however, and'it is also not essential' that the conductor extend the entire length of the section. The reference char acter J designates anauxiliary source of voltage,and, ashere shown, is a-transformer havwet its resistance is comparatively low, but

when the ballast is dry its resistance is comparatively high. The circuit for the sec- 'ondary of transformer J is so adjust-2d that when the ballast between auxiliary conductor B and the track'rails' is dry so thatthe cur rent flowing in this circuit is relatively small,

relay -H is open, whereas when the ballast is wet so that'tlie current flowing in this circuit isrelatively high, relay His closed.

The primary of'transformer T includes two portions 15 and15; When'relay His open, contactgl3 ofjthis relay includes both portions in the circuit between terminals 8 and 9, whereas when relay H is closed this contact'connects only the p ortion 15 of the primary winding with terminals 8 and 9. Interposed between the secondary of trans former T and the track rail 1? is a limiting reactance K having two portions 14 and 141.

When relay His open contact 12 of this relay connects only the portion 14 in the secondary circuit of transformer T, whereas when relay H is closed this contact connects both portions 14 and 14 in the signalcircuit. It follows that in dry weather both of the portions 15 and 15 of the primary of transformer T will be supplied with voltage, and only the portion 14 of the reactance K will be interposed in the secondary, circuit, so

thatrelatively low voltage will be app'lied to'the track rails land In 'Wetweather, however, only the portion 15 of the primary of transformer T will be supplied with voltage and bothportions 1% and of reacta'n'ce K'willbe included in the circuit for the sec: ondary of this transformer, so that relatively h gh vol age'will b app d to there n and i The reason for varying theamount of the reactanc'e K according to weather con ditions is to limit the short-circuit current drawn from the transformer T to substantially the same value regardless of-the voltage delivered by this transformer. By the short-circuit current I mean the current drawn from transformer T when a train is in the section E-F at or near the point Referring now to Fig. 2, the apparatus shown in this view is the same as that shown in Fig. 1, exceptthat the track relay, which is here designated R as two windings 6 and 7, the former of which is connected with t track rails and the latter of which is supplied ,with voltage from the alternating current terminals 8 and 9. In this form of the invention l vary the voltage applied to winding 7 v7 instead of varying the voltage applied to the traclr rails by transformer T, and as here shown this is accomplished by a limiting resistance M which is included in the circuit of this winding in dry weather but not in wet weather. That is to say, when relay H is deenergized, the circuit for winding 7 includes the back point of contact 12 and the resistance M, but when relay H is energized, the circuit for winding 7 includes the front point of contact; 12 and not the resistance M. It will be seen, therefore, that during dry weather, that is, when the voltage applied to winding 6 of relay R is relatively high, the voltage applied to winding 7 is relatively low, because of resistance M, whereas, during wet weather, when the voltage applied to winding 6 is relatively low, the voltage applied to winding 7 is relatively high, because resistance M is then not in circuit with winding 7. It follows that the total energy applied to relay B may be made substantially constant regardless of variation in weather conditions.

As shown in Fig. 2, the auxiliary conductor B is eliminated and a conductor 16-is sub-- I stituted therefor, this conductor 16 being connected with the ground at point Z.

Referring now to Fig. 3,1 have here shown a VVheatstone bridge W for the control of relay H. Three of the arms of this bridge 19, 20 and 21 are fixed resistances, whereas the fourth arm is the ballast resistance be tween the mid-point of reactance A and the ground at point Z. The secondary of transformer J is connected across two opposite points of the bridge W, whereas the relay H is connected across the other two opposite points of the bridge. Relay H is a polarized relay,,that is, it is responsive to reversals of As here shown, the contacts of relay H control a limiting resistance M, which is inv eluded in the circuit for winding 7 of relay R The parts'are so adjusted that in dry weather the contacts of relay H swing to the right, so that both'sections 17 and 18 of resistance M are included in the circuit for winding 7. As the ballast becomes wet, the current supplied to winding H decreases until this relay becomes substantially deenergized, whereupon contact23' assumes its int rmediate position and thereby cuts section 17 of resistance M out of the circuit for winding 7. ballast, relay H becomes energized in the other direction, so that contact 23 swings to the left and thereby cuts the entire resistance M out of the circuit for windingi. Itfollows that as the current supplied to the track winding 6 of relay E decreases in response to increased wetness of the ballast the current supplied to winding 7 of this relay increases and thereby tends to maintain substantially constant energization of the relay as a whole.

Referring now to Fig. l, the apparatus snown herein is substantially the same asthat shown in Pig. 3, except that the separate resistances l9 and 20 of the l Vheatstone bridge have been replaced by the two halves of the secondary of transformer J. The operation of the apparatus shown in Fig, 4 is the same as that of the apparatus shown in Fig. 3, and will be understood without further explanation.

Referring now to Fig. 5, the circuit for connected across the rails of sections E-F and FG, respectively. In dry weather relay H is d e-energized, so that relay P is de- ,energized and the resistance M is included in the circuit for relay winding 7. Inwet weather, however, relay H is energized, re-

lay P is energized, and the resistance M is current to winding 7 to offset the decreased supply of current to winding 6. If, however.

no means were provided to prevent it. relay H would become energized each time a train bridges the insulated joints 2 at pointF, and so I include in the circuit of this relay. a reslstance 25, which is normally shunted by a front contact 26 of track relay R and is also shunted by contact 28 of relay P when the latter relay is energized.

The operation of the apparatus shown in Fig. 5, is as follows: Assuming that relay H is de-energized, when a train moving toward the right enters sectionxF-G, it de-energizes Upon further saturation of the 'shuntech'thereby increasing the supply of relay R thereby opening the shuntaround resistance 25 at contact 26 and so preventing relay H from becoming energized. If, how ever, relay H is energized when the train enters section FG, relay P will be energized, 7

so that contact 28 will be closed, but since relay H is already energized,-no change occurs in the condition of the apparatus other than to open contact 26 of relay R The thermal relay P introduces a time element between the closing of relay H and the closing of contacts 27 and 28. If relay H should close before relay R opens when a train enters section F-G, this time interval will prevent contact 27 from shuntingresistance M, and so increasing the current in winding 7, until relay R opens. Of course, any other type of slow-acting relay may be substituted for the thermal relay P.

Although I have herein shown and de scribed only five forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention. v

Having thus described my invention, what I claim is:

1. In combination with a section of railway track provided With a source of track circuit voltage and a track relay, an auxiliary conductor in contact with the track ballast, and means for varying the voltage applied to a winding of said track relay in response to variations in the resistance of the ballast between said auxiliary conductor and the track rails.

2. In a railway signal system comprising a section of track, a source of track circuit voltage connected across the rails of said section, and a track relay having a first winding receiving energy from the rails of said section and a second winding supplied with voltage, the combination with the aforesaid instrumentalities of an auxiliary conductor in contact with the track ballast, and means responsive to variations in the resistance of the ballast between said conductor and the track rails for varying the voltage applied to the second winding of said track relay.

8. In combination with a section of railway track provided with a source of track circuit voltage and a track relay, an auxiliary conductor in contact with the track ballast, an auxiliary source of voltage connected with said conductor, and a track rail, an auxiliary relay included in circuit with said auxiliary source and arranged'to be closed or open ac cording as the ballast resistance is relatively low or relatively high, and means controlled by said auxiliary relay for varying the voltage applied to a winding of said track relay. at. In a railway signal system compr sing a section of track, a source of track circuit voltage connected across the rails of said secsource of voltage connected with said conductor and a track rail, an auxiliary relay included in circuit with said auxiliary source and arranged to be closed or open according as the ballast resistance is relatively low or relatively high, and means controlled by said auxiliary relay for varying the voltage a plied to the track rails by said first source.

5. In combination with a section'of railway track provided with a source of track circuit voltage and atrack relay, an auxiliary relay responsive to variations in the resistance of the rack ballast, and means controlled by a contact of said auxiliary relay for varying the voltage applied to a, winding of said track relay.

6. In a-railway signal system comprising a section of track, a source of track circuit voltage connected across the rails of said section, and a track relay having a first winding receiving energy from the rails of said section and a second winding supplied with voltage, the combination with the aforesaid inst-rumentalities of an auxiliary relay responsive to variations in theresistanceof the track ballast, and means controlled by a contactof said auxiliary relay for varying the voltage applied to the second winding of said track relay.

7. In combination with a section of rail way track provided with a source of track circuit voltage and a track relay, an auxiliary conductor in contact with the track ballast, an impedance connected across the rails of said section, an auxiliary source of voltage connected with said conductor and an inter-. mediate point in said impedance, an auxiliary relay included in circuit with said auxiliary source, and means controlled by said auxiliary v relay for varying the voltage applied to a winding of said track relay.

In testimony whereof I aflix my signature.

ANDREW A. SKENE.

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